Patent GB-1075667-A (GB)
Title: Power propelled appliances
IPC: A01D34/47
Filed: 1964-07-13
Abstract: 1,075,667. Controlling vehicles. HOOVER Ltd. July 13, 1964 [July 15, 1963], No. 28786/64. Heading B7H. [Also in Division F2] A self-propelled appliance controlled by a person walking therewith comprises a power source, driving wheels or endless-tracks, transmission means including a coupling in which a driven member driven by the power source and a driving member driving the wheels are arranged to slip during all normal operation of the appliance, a manually operable control device actuated by force applied thereto as a result of relative movement between appliance and person, and means interconnecting the control device and the driving member of the coupling to cause translational movement of the driving member upon actuation of the control device and thereby vary the extent of the slip as a function of the applied force. As shown, the handle 2 of a suction cleaner carries a slidable handgrip 37 connected by bellows 38, 40 and a flexible plastics pipe 39 containing a compressible fluid to a linkage 40<SP>1</SP>, 42, 42<SP>1</SP> controlling swinging about a pivot 36<SP>1</SP> of a lever 36 (shown only in part) carrying a pulley 12 driven by a belt 11 from a pulley 10 on a motordriven shaft 8. A bevelled friction element 33 on the pulley 12 engages upon swinging of the pulley 12 to either side of a neutral position with a friction element 34 or 35 on one of driving members 27, 28 and urges the driving member into contact with a friction disc 31 or 32 on one of driven members 29, 30 secured to a shaft 20. Pulleys 14, 15 at each end of the shaft 20 are connected by belt drives 16, 17 to the driven wheels 4 of the cleaner and are connected to rotate with the shaft by engagement under adjustable spring pressure with friction discs on the shaft, slipping of the pulleys 14, 15 providing differential action between the wheels 4. In another embodiment (Fig. 10, not shown) toothed bevel gearing replaces the bevelled friction elements. In a further embodiment a mechanical linkage replacing the bellows 38, 40 and connecting pipe 39 includes a spring for damping the control action. In an alternative arrangement (Fig. 12, not shown) a handle (86) is mounted on a lever (90) pivotally connected to the frame of the appliance and having a pin and slot connection (101, 102) with a lever (96) whereby axial forces on the handle swing the lever (96) to engage a friction member (13) on a pulley (93) with friction discs (104, 105) on a shaft (90). In Fig. 11 (not shown) axial forces on a handle (77) are transmitted by a lever (79) and a link (81) to a lever (74) carrying an endless-track (73) extending around oppositely rotating wheels (71, 72). The wheels slip relatively to the track by an amount depending on movement of the lever (74) which increases the pressure exerted on the track (73) by one wheel at the expense of the other. An appliance having such tracks on both sides may be steered by differential steering of the tracks by providing a forked handle for attachment to the levers (79). In a lever (126) pivoted on the ends of a handlebar (128) being linked to levers (139, 145) controlling engagement of driven members (121, 122) by friction discs on driving members (123, 124) connected through bevel gearing 117, 118, 119 and a belt drive (114) to an electric motor or I.C. engine (112). Traction wheels (109) at each end of a common shaft are driven from a shaft (120) carrying the driven members (121, 122) by a belt drive (149) and a gear (153) engaging a toothed rim (154) within one of the wheels (109).